Generous Application

Riddle
Riddles are little poems or phrases that pose a question that needs answering. Riddles frequently rhyme, but this is not a requirement.

Packaged in a jar or perhaps a tub
Enjoyed from Wellington to Timbuktu

Although some may think I come from a nut
Nutritionists would know that I do not

Use me to form a delicious lunch slice
Tastier yet with my fruity topper

What am I?

Hint

The answer is found in a certain spot
which enables this riddle to rhyme not.

Answer

peanut butter

Regarding the hint, if you have another look at the riddle, you'll see that the first letters of each line together spell the word "peanut", and the last letters of each line together spell the word "butter" (not including the "What am I?" line). Since I decided that the riddle's lines would end with "butter", I wasn't able to make it rhyme.

lines 1-2: Peanut butter is available in jars or tubs, and is "enjoyed" throughout the world.
lines 3-4: Although "nut" is in "peanut", a peanut is a legume, not a nut. Therefore, peanut butter does not "come from a nut".
lines 5-6: The phrase "lunch slice" refers to a sandwich, and the phrase "fruity topper" refers to jam or jelly.

The title alludes to applying or spreading a generous amount of peanut butter on a sandwich.